I'd actually say demand for an old pentium is higher. A very small amount of todays computer users ever used amigas for anything other than a games console, and the total number of computer users in 1994 is a mere fraction of today. One person i've spoke to was very surprised his A500 was actually a computer. He was actually wondering why they put a keyboard on it "when none of the games used it". He was also surprised it came with a mouse.
In comparison, a few of my friends use pentium 1/windows 98/crt monitor setups even today. That way they save to money thats better spent on beer and guitars and things, and they can run modern web browsers and word processors to boot.
The daft cost of accelerator cards or the amiga market is quite simply, dumb. These systems are far outclassed in ability and ease of use by even the most crap celeron system, the one thing that they are actually useful for is games. Remember, £10 snes.